The environment of the Education Network is relatively complex, and the Education Network is accessed in a complete CERNET mode in some colleges and in a hybrid access mode of Chinese Unicom, Chinese Telecom and Chinese Mobile in some other colleges. Due to the limitation of charging and the network itself, part of the colleges encounter the problem that they cannot access overseas websites. A solution in the prior art is to build a proxy server and send an HTTP access request of a browser to the proxy server. The proxy server is a server for a client and a client for a server, namely, it serves as an intermediary between the actual client and server ends.
There are two methods related to the proxy server in the prior art.
The first one is a technical solution related to a web proxy server:
A web proxy server is also known as online proxy server. The web proxy server is a proxy server program running in a webpage, and can be accessed by inputting a web address and selecting a proxy server without any setting. The web proxy server caches webpages and files of a remote website for the client so that the client can browse the remote website more quickly and securely. Some web proxy server websites are updated every day, so that the speed of accessing a link is also relatively fast. The principle of the web proxy server may be briefly summarized as follows: user's access—web proxy server—target website—returning to the user. However, due to the settings of such as webpage templates and protocols used by the web proxy server, it has the following drawbacks:
1) Since the web proxy server itself is a webpage and includes a lot of content, use of the web proxy server will consume a lot of traffic, and a website providing the web proxy server is probably confronted with problems such as depletion of the traffic or instability. Besides, the speed of surfing on the Internet via the web proxy server is slower than of normal surfing.
2) Basically, all web proxy server websites have advertisements thereon. Even an advertisement freezing the webpage will occur after the user gets idle for a period of time, which can only be solved by finding SRC (src attribute is used to designate a picture position) of the JavaScript of the advertisement.
3) Due to limitations of protocol settings and templates used by the web proxy server, when other websites are accessed via the web proxy server, abnormity might occur upon accessing advanced websites based on such as AJAX. For example, there might be something wrong with items for such as supplementing content, publishing opinions and submitting votes. Besides, situations such as failure to display or abnormal display of styles might occur when the web proxy server is used.
The second method is the so-called transparent proxy server, namely, a client directly accesses a target website through a proxy server. The solution may be roughly described as follows: the client first establishes connection to the proxy server, then requests to establish connection to a target server or obtains a designated resource of the target server according to the proxy server protocol used by the proxy server. The solution can solve the drawbacks of the aforesaid web proxy server.
However, in this solution, once the client uses the proxy server, it will send all local http access requests to the proxy server, the proxy server then construct a DNS (Domain Name System) request according to the http access requests to query for the IP of the target website, and then obtains corresponding content from the target website and returns it to the client. As such, since all http access requests are totally delivered to the proxy server, the proxy server has excessive load and its performance is reduced. That is to say, in the prior art, if the client has an IP that belongs to a predetermined IP address library and cannot directly access websites outside the predetermined IP address library, when the client uses the proxy server to access websites outside the IP address library, all the client's HTTP access requests will be forwarded and received via the proxy server. Since all http requests are delivered to the proxy server, successive load is caused to the proxy server and the performance of the proxy server is reduced.